The weather observed at BOSTON, MA (KBOS) at 03:54 AM EDT was: The skies were mostly clear. Temperature: 39F ( 4C) Dewpoint: 21F ( -6C) Relative Humidity: 48% Winds from the WSW(250 degs) at 16 mph. Pressure: 1009.0 millibars. Altimeter:29.80 inches of mercury. The prevailing visibility was 10 miles.